Farmed Salmon Welfare: Crowding and Aggression

Atlantic salmon in net pens are stocked at densities that promote chronic stress and aggressive interactions. Evidence-based density management improves welfare and production outcomes.

Key Facts

Stocking density regulations for Atlantic salmon vary from 20 to 50 kg per cubic meter across jurisdictions
Higher densities are associated with increased fin damage, eye cataracts, and gill damage
Aggressive interactions including fin biting cause injuries that serve as disease entry points
Social hierarchy stress in crowded salmon reduces feeding motivation in subordinate individuals
Some premium Norwegian producers voluntarily maintain lower densities with demonstrated welfare benefits

Welfare Considerations

Crowding stress in farmed salmon is chronic, pervasive, and manageable. The same welfare indicators — fin damage, eye damage, reduced growth in subordinate fish — that identify crowding problems also cost money through reduced weight gain and increased mortality. Lower stocking density requirements make welfare and economic sense simultaneously. Consumer demand for welfare-certified salmon with documented density limits is creating market incentives for voluntary improvement.

What You Can Do

Choose salmon from producers with documented low stocking density standards
Support RSPCA Assured and similar certifications with explicit density requirements
Advocate for maximum stocking density requirements in national aquaculture welfare regulations
Follow research on the relationship between stocking density, welfare indicators, and production outcomes